 |
 |
 |
|
Abstract and Manuscript Management System - Abstract Detail |
|
| Main Menu | Abstracts | |
| Speaker: | |
| Title: | |
| Topic Group: | |
| E-mail: | |
| Co-Authors: | |
| Abstract: |
Germany plays a leading role in industrial computed tomography (CT) application and research in the field of dimensional measurements, i.e. in performing coordinate measurements for assessing information on the geometry of technical parts. This paper describes the current activities in this field and the present and future power of this emerging coordinate measuring technology. Furthermore, aspects of the traceability of this measurement technique and of the use of dedicated material standards are discussed. Computed tomography using X-rays is an established non-destructive testing technique. For more than 20 years CT has been used to analyze technical parts like cast aluminum cylinder heads for defects (e.g. pores, shrink holes, discontinuities). In recent years the application has increasingly focused on the geometry measurement of industrial part dimensions. In fact, nowadays dedicated CT systems are commercially available, with the primary purpose of being used as coordinate measurement machines (CMMs). The advantage of this emerging technique is the complete and non-destructive determination of the inner and outer geometry with an outstandingly high measurement point density. The latest development are CT-based CMMs which are dedicated for the measurement of microparts and multisensor CMMs featuring CT operation in combination with optical sensors and tactile probing. However, an important aspect of all coordinate measurements is the traceability of the geometry information obtained. To achieve traceability, several one-, two-, or three-dimensional material standards have been developed in recent years by PTB (the German national metrology institute), BAM (the German national material testing institute) and partners, within research and industrial projects. Material standards with a high information content are the sphere calotte plate made of zerodur, a glass ceramic with low thermal expansion, or the sphere calotte cube made of titanium, which can provide 2D or 3D information for CT system testing and correction, respectively. In general, the aim is to develop standards and test procedures comparable to classical CMM metrology and guidelines (e.g. ISO 10360) for performance testing and verification. Hence, in this paper micro-CT measurement results which demonstrate the successful use of material standards for the performance testing of state of the art CT systems are presented and discussed in detail. |
|
NCSL International © 1996-2008 All Content. October 07, 2008 11:26 PM |